Osmotic stress-responsive promoter upstream transcripts (PROMPTs) act as carriers of MYB transcription factors to induce the expression of target genes in Populus simonii

Abstract As the largest group of MYB family transcription factors, R2R3-MYB proteins play essential roles during plant growth and development. However, the structural basis underlying how R2R3-MYBs recognize the target DNA remains elusive. Here, we report the crystal structure of Arabidopsis WEREWOLF (WER), an R2R3-MYB protein, in complex with its target DNA. Structural analysis showed that the third α-helices in both the R2 and R3 repeats of WER fit in the major groove of the DNA, specifically recognizing the DNA motif 5′-AACNGC-3′. In combination with mutagenesis, in vitro binding and in vivo luciferase assays, we showed that K55, N106, K109 and N110 are critical for the function of WER. Although L59 of WER is not involved in DNA binding in the structure, ITC analysis suggested that L59 plays an important role in sensing DNA methylation at the fifth position of cytosine (5mC). Like 5mC, methylation at the sixth position of adenine (6mA) in the AAC element also inhibits the interaction between WER and its target DNA. Our study not only unravels the molecular basis of how WER recognizes its target DNA, but also suggests that 5mC and 6mA modifications may block the interaction between R2R3-MYB transcription factors and their target genes.

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Multiple Functions of MYB Transcription Factors in Abiotic Stress Responses

International Journal of Molecular Sciences ◽

10.3390/ijms22116125 ◽

2021 ◽

Vol 22 (11) ◽

pp. 6125

Author(s):

Xiaopei Wang ◽

Yanli Niu ◽

Yuan Zheng

Keyword(s):

Transcription Factors ◽

Stress Responses ◽

Abiotic Stresses ◽

Target Genes ◽

Regulatory Mechanism ◽

Adaptation Process ◽

Myb Transcription Factors ◽

Protein Levels ◽

Myb Proteins ◽

Efficient Mechanisms

Plants face a more volatile environment than other organisms because of their immobility, and they have developed highly efficient mechanisms to adapt to stress conditions. Transcription factors, as an important part of the adaptation process, are activated by different signals and are responsible for the expression of stress-responsive genes. MYB transcription factors, as one of the most widespread transcription factor families in plants, participate in plant development and responses to stresses by combining with MYB cis-elements in promoters of target genes. MYB transcription factors have been extensively studied and have proven to be critical in the biosynthesis of secondary metabolites in plants, including anthocyanins, flavonols, and lignin. Multiple studies have now shown that MYB proteins play diverse roles in the responses to abiotic stresses, such as drought, salt, and cold stresses. However, the regulatory mechanism of MYB proteins in abiotic stresses is still not well understood. In this review, we will focus mainly on the function of Arabidopsis MYB transcription factors in abiotic stresses, especially how MYB proteins participate in these stress responses. We also pay attention to how the MYB proteins are regulated in these processes at both the transcript and protein levels.

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AcoMYB4, an Ananas comosus L. MYB Transcription Factor, Functions in Osmotic Stress through Negative Regulation of ABA Signaling

International Journal of Molecular Sciences ◽

10.3390/ijms21165727 ◽

2020 ◽

Vol 21 (16) ◽

pp. 5727

Author(s):

Huihuang Chen ◽

Linyi Lai ◽

Lanxin Li ◽

Liping Liu ◽

Bello Hassan Jakada ◽

...

Keyword(s):

Signal Transduction ◽

Transcription Factors ◽

Salt Stress ◽

Osmotic Stress ◽

Germination Rate ◽

Soluble Sugar ◽

Ananas Comosus ◽

Myb Transcription Factor ◽

Myb Transcription Factors ◽

Aba Biosynthesis

Drought and salt stress are the main environmental cues affecting the survival, development, distribution, and yield of crops worldwide. MYB transcription factors play a crucial role in plants’ biological processes, but the function of pineapple MYB genes is still obscure. In this study, one of the pineapple MYB transcription factors, AcoMYB4, was isolated and characterized. The results showed that AcoMYB4 is localized in the cell nucleus, and its expression is induced by low temperature, drought, salt stress, and hormonal stimulation, especially by abscisic acid (ABA). Overexpression of AcoMYB4 in rice and Arabidopsis enhanced plant sensitivity to osmotic stress; it led to an increase in the number stomata on leaf surfaces and lower germination rate under salt and drought stress. Furthermore, in AcoMYB4 OE lines, the membrane oxidation index, free proline, and soluble sugar contents were decreased. In contrast, electrolyte leakage and malondialdehyde (MDA) content increased significantly due to membrane injury, indicating higher sensitivity to drought and salinity stresses. Besides the above, both the expression level and activities of several antioxidant enzymes were decreased, indicating lower antioxidant activity in AcoMYB4 transgenic plants. Moreover, under osmotic stress, overexpression of AcoMYB4 inhibited ABA biosynthesis through a decrease in the transcription of genes responsible for ABA synthesis (ABA1 and ABA2) and ABA signal transduction factor ABI5. These results suggest that AcoMYB4 negatively regulates osmotic stress by attenuating cellular ABA biosynthesis and signal transduction pathways.

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MYB transcription factors in plants

AccessScience ◽

10.1036/1097-8542.yb130014 ◽

2015 ◽

Keyword(s):

Transcription Factors ◽

Myb Transcription Factors

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Global Genome Expression Analysis of Transcription Factors under PEG Osmotic Stress in Rice Root System

ACTA AGRONOMICA SINICA ◽

10.3724/sp.j.1006.2009.01030 ◽

2009 ◽

Vol 35 (6) ◽

pp. 1030-1037 ◽

Cited By ~ 1

Author(s):

Ting-Chen MA ◽

Rong-Jun CHEN ◽

Rong-Rong YU ◽

Han-Lai ZENG ◽

Duan-Pin ZHANG

Keyword(s):

Transcription Factors ◽

Osmotic Stress ◽

Root System ◽

Expression Analysis ◽

Rice Root ◽

Genome Expression

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The roles of MYB transcription factors on plant defense responses and its molecular mechanism

Hereditas (Beijing) ◽

10.3724/sp.j.1005.2008.01265 ◽

2008 ◽

Vol 30 (10) ◽

pp. 1265-1271 ◽

Cited By ~ 8

Author(s):

Lei LIU

Keyword(s):

Transcription Factors ◽

Plant Defense ◽

Molecular Mechanism ◽

Defense Responses ◽

Plant Defense Responses ◽

Myb Transcription Factors

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MYB Transcription Factors and Its Regulation in Secondary Cell Wall Formation and Lignin Biosynthesis during Xylem Development

International Journal of Molecular Sciences ◽

10.3390/ijms22073560 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3560

Author(s):

Ruixue Xiao ◽

Chong Zhang ◽

Xiaorui Guo ◽

Hui Li ◽

Hai Lu

Keyword(s):

Cell Wall ◽

Transcription Factors ◽

Secondary Wall ◽

Secondary Cell Wall ◽

Lignin Biosynthesis ◽

Cell Wall Formation ◽

Long Distance ◽

Secondary Cell Wall Formation ◽

Myb Transcription Factors ◽

Wall Formation

The secondary wall is the main part of wood and is composed of cellulose, xylan, lignin, and small amounts of structural proteins and enzymes. Lignin molecules can interact directly or indirectly with cellulose, xylan and other polysaccharide molecules in the cell wall, increasing the mechanical strength and hydrophobicity of plant cells and tissues and facilitating the long-distance transportation of water in plants. MYBs (v-myb avian myeloblastosis viral oncogene homolog) belong to one of the largest superfamilies of transcription factors, the members of which regulate secondary cell-wall formation by promoting/inhibiting the biosynthesis of lignin, cellulose, and xylan. Among them, MYB46 and MYB83, which comprise the second layer of the main switch of secondary cell-wall biosynthesis, coordinate upstream and downstream secondary wall synthesis-related transcription factors. In addition, MYB transcription factors other than MYB46/83, as well as noncoding RNAs, hormones, and other factors, interact with one another to regulate the biosynthesis of the secondary wall. Here, we discuss the biosynthesis of secondary wall, classification and functions of MYB transcription factors and their regulation of lignin polymerization and secondary cell-wall formation during wood formation.

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Regulatory Network Analysis in Estradiol-Treated Human Endothelial Cells

International Journal of Molecular Sciences ◽

10.3390/ijms22158193 ◽

2021 ◽

Vol 22 (15) ◽

pp. 8193

Author(s):

Daniel Pérez-Cremades ◽

Ana B. Paes ◽

Xavier Vidal-Gómez ◽

Ana Mompeón ◽

Carlos Hermenegildo ◽

...

Keyword(s):

Endothelial Cells ◽

Transcription Factor ◽

Transcription Factors ◽

Regulatory Network ◽

Mirna Target ◽

Target Genes ◽

Functional Characterization ◽

Human Endothelial Cells ◽

Mrna Targets ◽

Canonical Pathways

Background/Aims: Estrogen has been reported to have beneficial effects on vascular biology through direct actions on endothelium. Together with transcription factors, miRNAs are the major drivers of gene expression and signaling networks. The objective of this study was to identify a comprehensive regulatory network (miRNA-transcription factor-downstream genes) that controls the transcriptomic changes observed in endothelial cells exposed to estradiol. Methods: miRNA/mRNA interactions were assembled using our previous microarray data of human umbilical vein endothelial cells (HUVEC) treated with 17β-estradiol (E2) (1 nmol/L, 24 h). miRNA–mRNA pairings and their associated canonical pathways were determined using Ingenuity Pathway Analysis software. Transcription factors were identified among the miRNA-regulated genes. Transcription factor downstream target genes were predicted by consensus transcription factor binding sites in the promoter region of E2-regulated genes by using JASPAR and TRANSFAC tools in Enrichr software. Results: miRNA–target pairings were filtered by using differentially expressed miRNAs and mRNAs characterized by a regulatory relationship according to miRNA target prediction databases. The analysis identified 588 miRNA–target interactions between 102 miRNAs and 588 targets. Specifically, 63 upregulated miRNAs interacted with 295 downregulated targets, while 39 downregulated miRNAs were paired with 293 upregulated mRNA targets. Functional characterization of miRNA/mRNA association analysis highlighted hypoxia signaling, integrin, ephrin receptor signaling and regulation of actin-based motility by Rho among the canonical pathways regulated by E2 in HUVEC. Transcription factors and downstream genes analysis revealed eight networks, including those mediated by JUN and REPIN1, which are associated with cadherin binding and cell adhesion molecule binding pathways. Conclusion: This study identifies regulatory networks obtained by integrative microarray analysis and provides additional insights into the way estradiol could regulate endothelial function in human endothelial cells.

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Role of Satb1 and Satb2 Transcription Factors in the Glutamate Receptors Expression and Ca2+ Signaling in the Cortical Neurons In Vitro

International Journal of Molecular Sciences ◽

10.3390/ijms22115968 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5968

Author(s):

Egor A. Turovsky ◽

Maria V. Turovskaya ◽

Evgeniya I. Fedotova ◽

Alexey A. Babaev ◽

Viktor S. Tarabykin ◽

...

Keyword(s):

Transcription Factors ◽

Nmda Receptor ◽

Cortical Neurons ◽

Target Genes ◽

Cortical Cell ◽

Inhibitory System ◽

Selective Agonist ◽

Genes Encoding ◽

Deficient Mice

Transcription factors Satb1 and Satb2 are involved in the processes of cortex development and maturation of neurons. Alterations in the expression of their target genes can lead to neurodegenerative processes. Molecular and cellular mechanisms of regulation of neurotransmission by these transcription factors remain poorly understood. In this study, we have shown that transcription factors Satb1 and Satb2 participate in the regulation of genes encoding the NMDA-, AMPA-, and KA- receptor subunits and the inhibitory GABA(A) receptor. Deletion of gene for either Satb1 or Satb2 homologous factors induces the expression of genes encoding the NMDA receptor subunits, thereby leading to higher amplitudes of Ca2+-signals in neurons derived from the Satb1-deficient (Satb1fl/+ * NexCre/+) and Satb1-null mice (Satb1fl/fl * NexCre/+) in response to the selective agonist reducing the EC50 for the NMDA receptor. Simultaneously, there is an increase in the expression of the Gria2 gene, encoding the AMPA receptor subunit, thus decreasing the Ca2+-signals of neurons in response to the treatment with a selective agonist (5-Fluorowillardiine (FW)). The Satb1 deletion increases the sensitivity of the KA receptor to the agonist (domoic acid), in the cortical neurons of the Satb1-deficient mice but decreases it in the Satb1-null mice. At the same time, the Satb2 deletion decreases Ca2+-signals and the sensitivity of the KA receptor to the agonist in neurons from the Satb1-null and the Satb1-deficient mice. The Satb1 deletion affects the development of the inhibitory system of neurotransmission resulting in the suppression of the neuron maturation process and switching the GABAergic responses from excitatory to inhibitory, while the Satb2 deletion has a similar effect only in the Satb1-null mice. We show that the Satb1 and Satb2 transcription factors are involved in the regulation of the transmission of excitatory signals and inhibition of the neuronal network in the cortical cell culture.

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